CraigT82

Yes I wondered about that, I think I read somewhere that the field stop diameter is broadly similar to the focal length but I might be wrong.  Actually thinking about it some more that's not quite right, as a 32mm plossl will have a much smaller field stop than a 31mm nagler.  I do have a plastic vernier caliper at home which I could use to measure the actual diameter without risking scratching the glass

I will report back once I've used it in anger!

Thanks Stu, I did worry about that before starting out with the mod, but as far as I can tell it should be fine for use with longer FL EPs.

The secondary is actually oversized by some margin, it's 40mm (31% CO).  The image below show that with a 28mm EP there will be a 0.3 magnitude drop at the edges, which I think is acceptable (however I've only guessed at the 'diagonal to focal plane distance', I need to measure it and re-run the chart).

I think with this F5 scope 28mm EPs are about as long as I'd go, my current 32mm panaview gives a 6.4mm exit pupil which is a bit too much.

Thanks!  There are still some issues with the mod that needs sorting out, the focuser drawtube is quite long as needs cutting down a bit as it intrudes into the lightpath when my EPs are at focus (the other option is to collapse the trusses an inch or two to shift the focal plane further out - but then I'd be worried about light loss from the secondary being too far forward).

Also as the drawtube protudes into the OTA it prevents the trusses from collapsing fully, the last photo shows how much the focuser has to be wound out to allow the bottom of the drawtube to clear the OTA.  I think for airline travel I'd remove the focuser and store it within the OTA with suitable foam padding and protection for the mirrors.

Once I'm happy that the whole thing works, I'm going to cut off the original focuser and move the new focuser around to take up the original position, that's simply a matter of drilling 4 new holes for the ends of the steel strips to attach to the UTA.

Hi all, been busy this afternoon adding a 2" Crayford to my heritage 130p.

My idea is to turn it into wide field DSO travel scope for airline transport to very dark skies (I'm visiting Tasmania I'm January - very excited about super dark southern skies there).

I've always thought it's a great little scope which punches about its weight, just let down by its primitive  1.25" focuser. I bought a TS 2" single speed Crayford to fit to the OTA, this particular focuser is relatively lightweight (500g) compared with other aftermarket crayfords which are closer to 1kg. The weight matters as the trusses will only take so much added before it begins to twist and flex (about 1.3kg by my testing before the collimation is affected). 

I can now use weighty 2" widefield EPs (up to 750g) with this scope, and with a bit more fettling it will be a superb travel scope. 

Swung by Maplins on the way home tonight and they had the swish grey cases on sale.  Since it's payday I treated myself (and my EPs!).

46 minutes ago, F15Rules said:

I've posted pictures of my Vixen ED103s doublet here before I think, but here she is on my new Porta II mount for quick grab and go sessions.

Very smooth and the manual slo mos are great, no backlash.

I've fitted 3 hardwood leg extensions which can increase height (not needed with this scope) and/or aid improved stability as the ali legs don't have to be extended so far.

The weather has been so lousy where I live this year, but this set up at least allows me to pick up the rig from the garage and move it 4 metres onto my drive with no effort whatsoever, no alignment with Polaris etc, just point and shoot!

Is pretty steady, damps down with a big ES eyepiece in 2-3 seconds maximum :-)

Dave

I've never seen tha Vixen HAL tripod in the flesh... Does it come with the wooden inserts at the bottom of the legs or is that something you've done?  It's genius if it is!

1 hour ago, cloudsweeper said:

All these cases are great, and their contents clearly much loved and respected.

Now here's the thing.

Can someone with loads of experience state (without much fear of contradiction) which EPs are generally considered the best, both for - shall we say - general use, and wide angle use?

Or am I over-simplifying things?

Might give me something else to put on my list!

Cheers,

Doug.

Why isn't there an 'opens can of worms' emoji?! 

I'm  not sure there is such a thing as 'the best' EP. Only 'the best for you'.

2 hours ago, D Wright said:

Here is my Orion GX250 f4.9 with mods I have done myself

Looking good! What do you use to power your fans? 

My own modded 200p skyliner tube, on a poor old CG5 struggling under the weight.  Note water bottle hanging off cw bar for extra weight.  You also get an idea of the LP I have to battle! 

Here's my newly acquired Opticstar AR90S.... A nifty little 90mm f5.6 achro set up as a wide field companion to my skyliner on my skytee.

Im actually quite impressed with this little Frac. I bought it purely ft widefield viewing with my ES68 34mm EP giving a 4.5 degree TFoV (and also to use as an airline portable travel scope) but I've jest been out checking it out on Jupiter with my 6.5mm Morpheus and it shows a good deal of detail, there's also plenty of CA as expected but not so much as to detract from the detail I feel. 

The dob base of the bresser also looks like it's been designed for disassembly, which would be good for storing/transporting the scope when space is tight. 

However, the sheer number of skyliner owners means that if you ever have a problem with it or need advice on modifications then there's plenty of people to offer help. The bresser is relatively new so not to many of them around. 

If you want to add the skyliner to an EQ mount you can pick up a pair of tube rings for £30-40 (plus another £30-40 ish for a dovetail) 

Nice job! That's a really professional looking finish you've managed there 

Any half decent scope really deserves a good focuser, it's such a critical part of the scope and so many new scopes ship with sub-par focusers its criminal really. But hey-ho... At least it leaves those of us who like to fettle, something to fettle with! (And synta scopes are ripe for a bit of self improvement as they usually are a bit shoddy but have good quality optics, which is what counts at the end of the day). 

Latest sets of eyepieces, optimised now for Bino viewing.

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Purchased the 24mm Panoptics at the IAS today.

Is that a Tak scope on the right??

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My first proper EP case (was previously carrying everything around in an old wine presentation box